Ratner is expected to put his offer to the Signet board in the next few weeks.

If successful, the deal would mark a dramatic return by Ratner to the companies he ran before an infamous speech at a City dinner destroyed his business and his reputation.

Ratner, 56, whose interest in H Samuel became public this month, has decided to broaden his offer to include the more upmarket Ernest Jones and Leslie Davis stores.

Ratner is in advanced talks with a consortium of financial backers, led by the Royal Bank of Scotland, to raise funds for the deal. Accountancy firm BDO Stoy Hayward is helping him put the finishing touches to his offer.

'We are looking at Ernest Jones as well as H Samuel. It would be ridiculous to break them up,' Ratner told Financial Mail.

'I think I have more chance of being successful if I bid for both as I don't think any vendor would want to split them,' he added. The entrepreneur lost control of the Ratners empire, which included H Samuel and Ernest Jones, 15 years ago after joking that a product sold in his stores was 'total crap'.

The comment, made during a speech to the Institute of Directors in 1991, cost him his job and his personal fortune and wiped an estimated £500m off the company's value.

Asked for his view on the H Samuel range today, Ratner was still critical, but more diplomatic: 'They have Burberry prices and Matalan products,' he said.

The former Ratners business changed its name to Signet Group in 1993 as part of a restructuring plan.

Its key step was to change its focus to America where it owns Jared and the top-selling Kay brand. The group generates 76% of its profits in the States, while its UK chains are in decline.

Like-for-like sales at its 386 H Samuel stores fell 8.8% last year, while sales at Ernest Jones and Leslie Davis were down by 7.6%.

This month, it emerged that private equity giants Kohlberg Kravis Roberts and Apax Partners were mulling a £2.3bn offer for the entire Signet Group. So far though, they have not made a formal approach to the company.

Their interest followed Financial Mail's revelation in June that the company was in talks about a possible tie-up with its rival, America's Zale Corporation.

Ratner confirmed that he will proceed with his bid for the UK division regardless of a possible rival offer for the entire group.

'It is in the interest of Signet or KKR to make a clean break with the UK,' he said. Ratner, chief executive of Geraldonline.com, Britain's biggest online jewellery business, with annual sales of about £20m, is itching to get back to the High Street.

He believes he could repeat his success of 20 years ago when he turned an ailing H Samuel into a thriving business with annual profits of £60m within 18 months. Signet will report interim results on Wednesday. Analysts expect profits for the first half to rise from £52.1m to £58.6m.

Ratner launched geraldonline. com three years ago and the internet site boasts that it can offer jewellery more cheaply than High Street stores by taking advantage of both the lower costs of internet selling and sourcing products from India.

Ratner's rise and fall is even set to be the subject of a musical produced by the BBC. Simon Nye, author of sitcom Men Behaving Badly, has been drafted in to write the script.